[PATCH v8 01/10] dt-bindings: opp: Introduce opp-peak-kBps and opp-avg-kBps bindings

Georgi Djakov
2020-05-12T12:53:58Z

From: Saravana Kannan <saravanak@google.com>

Interconnects often quantify their performance points in terms of
bandwidth. So, add opp-peak-kBps (required) and opp-avg-kBps (optional) to
allow specifying Bandwidth OPP tables in DT.

opp-peak-kBps is a required property that replaces opp-hz for Bandwidth OPP
tables.

opp-avg-kBps is an optional property that can be used in Bandwidth OPP
tables.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---
v8:
* Picked reviewed-by tags.
* Changes on wording.

Documentation/devicetree/bindings/opp/opp.txt | 17 ++++++++++++++---
.../devicetree/bindings/property-units.txt | 4 ++++
2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
index 68592271461f..9d16d417e9be 100644
--- a/Documentation/devicetree/bindings/opp/opp.txt
+++ b/Documentation/devicetree/bindings/opp/opp.txt
@@ -83,9 +83,14 @@ properties.

Required properties:
- opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer. This is a
- required property for all device nodes but devices like power domains. The
- power domain nodes must have another (implementation dependent) property which
- uniquely identifies the OPP nodes.
+ required property for all device nodes, unless another "required" property to
+ uniquely identify the OPP nodes exists. Devices like power domains must have
+ another (implementation dependent) property.
+
+- opp-peak-kBps: Peak bandwidth in kilobytes per second, expressed as an array
+ of 32-bit big-endian integers. Each element of the array represents the
+ peak bandwidth value of each interconnect path. The number of elements should
+ match the number of interconnect paths.

Optional properties:
- opp-microvolt: voltage in micro Volts.
@@ -132,6 +137,12 @@ Optional properties:
- opp-level: A value representing the performance level of the device,
expressed as a 32-bit integer.

+- opp-avg-kBps: Average bandwidth in kilobytes per second, expressed as an array
+ of 32-bit big-endian integers. Each element of the array represents the
+ average bandwidth value of each interconnect path. The number of elements
+ should match the number of interconnect paths. This property is only
+ meaningful in OPP tables where opp-peak-kBps is present.
+
- clock-latency-ns: Specifies the maximum possible transition latency (in
nanoseconds) for switching to this OPP from any other OPP.

diff --git a/Documentation/devicetree/bindings/property-units.txt b/Documentation/devicetree/bindings/property-units.txt
index e9b8360b3288..c80a110c1e26 100644
--- a/Documentation/devicetree/bindings/property-units.txt
+++ b/Documentation/devicetree/bindings/property-units.txt
@@ -41,3 +41,7 @@ Temperature
Pressure
----------------------------------------
-kpascal : kilopascal
+
+Throughput
+----------------------------------------
+-kBps : kilobytes per second